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Old 08-06-2019, 05:00 AM
Anothernoob Anothernoob is offline
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Default Boma 1800w can't get full speed

Hi guys. First time poster but have gained much knowledge front this site!

So, starting my project. 1800w boma motor as mentioned.
I tried it with my old ebike controller, 45a sine wave with programmable lcd. Tried all 36 phase/hall combos. Two worked, but only very slowly and kinda rough.

Tried a cheaper ebike controller, not programmable and it was definitely better. But felt like it wouldn't get to full rpm and was "noisy" at full throttle. It was definitely slower than it should be.
52 volt battery was at 56 volts

Any suggestions?

I've ordered a tdpro controller but it's got me pretty stumped.

I have a good understanding of bldc hub motors but these are new to me.
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Old 08-06-2019, 08:00 AM
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itsid itsid is offline
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I'd say your programmable controller is what you need.

I can't see how you get to 36 variations of phase hall combos
Phases ABC and ACB are the only two variations for a set of three wires;
and the only thing it variates is to reverse rotation.
HE is slightly more complicated since there are three options
corresponding sensor is opposite, leading or trailing the coil
depends on the motor.. you can look it up in the manual btw
(for all I know it's a leading sensor)

since the sensors need to have the exact same order as the coils (ABC or ACB)
you get six different wiring setups
ABC & abc bca or cab
ACB & acb cba or bac

And since the wires are color coded most of the time..
you can just color match the controller wires to the motor wires
(say blue to blue, red to green and green to red; for both, the motor and the controller)

aaanyways...
the controller is likely programmed to limit the current
(or it's a peak 45A controller in which case it might be too small *shrugs*)

So slow running is based on misprogramming..
reprogram the controller for your motor and it'll be good.

'sid
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Old 08-06-2019, 02:48 PM
Anothernoob Anothernoob is offline
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A peak 45a controller is plenty big enough to spin a tiny unloaded 1800w motor.

And you're right it could be the programmable controller that's the issue, but that doesn't explain the non programmable controller not working either.

I'm leaning towards a 60/120 degree mismatch.

Will flip middle hall sensor today to confirm.
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Old 08-06-2019, 07:38 PM
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if the cheap controller has a choppy signal the motor will sound alot 'rougher' than with a smoothed sinusoidial output..

it not reaching full speed *shrugs* can't tell can't judge,
maybe it was limited by the controller
(overrev protection aka governor kicking in)
that'd also explain some of the noise
Maybe that cheap controller had a three position speed limiter you forgot to set (not uncommon on cheaper bike controllers)
Again.. can't tell

'sid
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